Light flashing apparatus



LIGHT FLASHING APPARATUS Filed Dec. 23, 1932` Patented Nov. 27, 1934 .UNITI-:D STA i Yrimasti LIGHT FLAsmNG APPARATUS Chauncey G. Suits, Schenectady, N. Y., assigner to General Electric Company, acorporation of New York Application December 23, 1932, SerialNo. 648,661

Claims. v (Cl. 176-124).

My invention relates to light flashing apparatus and particularly to an electric discharge lamp provided with means for causing it to become illuminated at regular intervals. AOne object of my 5 invention is the provision of improved apparatus for this purpose which is entirely free of relatively moving parts. Another object is the provision of such apparatus which is simple in construction,

efficient in operation and inexpensive to manufacture.

My invention will be better understood from the following description taken in connection with the accompanying drawing, and its scope will' be pointed out in the appended claims.

Referring to the drawing, Fig. 1 is a diagrammatic view illustrating an embodiment of my invention; and Figs. 2 and 3 represent two dif- .ferent forms of saturable core reactor forming a part of my invention.

In Fig. 1 the electric discharge lamp 1 has the main anode 2 and the cathode 3 connected through the ballast resistor 4 vwith the source ofsupply 5 of alternating current, which, for example, may be a 60 cycle, 110 volt source. The cathode 3 is a hot cathode being shown in the present case as provided with the heating coil 6 which connects at one end with the cathode and at the other end with the opposite side of the source of supply. The lamp 1 is of such a length that the discharge therein will not start between its cathode and main anode with the voltage employed, hence it is provided with one or more starting anodes 8,

two being represented in the present case, to which starting voltages are applied at each cycle of current supplied to the lamp.

For starting the lamp at regular recurring intervals in order to'produce an intermittent or flashing effect I have provided the non-linear resonant pulsation circuit 10 which connects 40 across the source of supply 5 and comprises the capacitor 11, the resistor l2, and the inductance element 13 which is represented as a saturable core reactor. This reactor is provided with'the saturating winding 14 which is supplied with rectied current from the rectier 15 connected through the resistor 16 with the source of supply 5. Circuit 10, which is termed non-linear resonant since it is a resonant circuit Vhaving a non-linear voltampere characteristic, at one side of the capacitor 11 connects with the supply lead which also connects with the cathode 3. The other side of the capacitor 11 connects by the lead 17 with the starting anodes 8 through resistors 18.

In. operation the alternating current in .the

non-linear circuit 10 undergoes regular variations `fact that the circuit becomes resonant at a low current value and when such a condition of resonance exists the resulting increase in current in the reactor 13 causes the impedance of the reactor to rise in a manner characteristic of biased core reactors to such a degree that the circuit is detuned from fits/resonant condition. The current then drops to the former low value only to rise again when resonance is thus reestablished. This sequence repeats itself regularly and indelinitely. .Since the cathode and the starting anodes 8 of the lamp are connected across the capacitor 11 the starting anodes haveapplied to them the voltage across the capacitor 11 which at every recurring pulsation of current in circuit 10 is sufficient to cause a starting of lamp 1, the voltage applied to the starting anodes between the pulsations being insufcient to cause the lamp to start. Inasmuchas the starting anodes 8 in this arrangement function in the manner of control grids, the current being supplied thereto through relatively high resistances, the power supplied to the starting anodes is considerably less than that which flows to the main anode. By connecting the vstarting anodes 8 with the capacitor 11 in the manner shown a. `small amount of power only is ,taken from the circuit 10 to shift the phase and change the magnitude of the voltage applied to the starting anodes thereby controlling theintermittent ilashing of the lamp.

It' will be noted that the above described apparatus is entirely electrical in its operation being devoid of any relatively moving parts. Furthermore, there are no moving contacts between which sparks may occur and 4produce radio interference.

For the sake of simplicity in Fig. I -I have shown the saturable core reactor 13 in a purely diagrammatic manner. Its actual construction, however, may for example be as shown in Fig. 2 where the core 19 has four legs, the winding of the reactor comprising coils 20 and' 21 being Wound in opposite directions' on the two inner legs and. connected in parallel with the alternating 11o legs.

vent alternating current from being induced in the direct current winding.

I have chosen the particular embodiments described above as illustrative of my invention and it will be apparent that. various other modifications may be made without departing from the spirit and scope of my invention which modications I aim to cover in the appended claims.

What I claim as new and desire to secure by 'Letters Patent of the United States, is:

1. In combination. a source of alternating current supply, a discharge lamp connected therewith and provided with a starting anode, and

means energized from said source and consisting of relatively xed parts for supplying to said anode a current which alternates at the same frequency as said current supplied and which pulsates at a frequency less than the frequency of A said current.

2. In combination, a discharge lamphaving a cathode, a main anode, and a starting anode, aY

source of alternating current supply connected to mperate said lamp, a non-linear resonant pulsat ing alternating current circuit including a saturable core reactor and a capacitor connected with said source, a connection between the cathode and one side of said capacitor and a. connection between the starting anode of said lamp and the other side of said capacitor.

3. In combination, a source of alternating current supply, a discharge lamp connected therewith and provided with a starting anode and means for causing the illumination of said lamp to pulsate with a frequency less than that of said alternating current, said means comprising a pulsating non-linear resonant circuit energized from said source of alternating current supply and connected with said starting anode.

4. In combination, a source of alternating current supply, a. discharge lamp connected therewith having a cathode, a main anode and a startingof alternating current supply and including animpedance element and means connecting one side of said element with said cathode and the other side thereof With said starting anode.

5. In combination, a source of alternating current Supply, a discharge lamp connected therewith and having a cathode, a main anode and a starting anode, and means for supplying an a1- ternating current to said starting anode which pulsates at a frequency less than the frequency of the current supplied to the lamp, said means comprising a pulsating non-linear resonant circuit energized from said source of supply and including a saturable core reactor and a capacitor whereby the illumination of the lamp pulsates with the pulsation frequency of the alternating current supplied to the starting anode.

; CHAUNCEY G. SUITS. 

